Windows are responsible for 30% of the heating and cooling loads in buildings. Thin film coatings on glass with color change capabilities could reduce energy consumption by reflecting unwanted radiation and transmitting needed radiation during daylight hours. Dynamic daylight and solar energy control in buildings presently can be achieved using smart windows based on electrochromic, gasochromic, liquid crystal, or electrophoretic devices. However, commercial versions of such technologies have not become popular due to their high costs. Furthermore, electrochromic windows require electrical energy to switch from one state to the other, and liquid crystal windows require continuous energy to remain in the transparent or colored state.
In view of the drawbacks of such technologies, the inventors developed alternative chromatic devices that are less expensive to produce and operate than existing devices. In particular, the inventors developed chromatic devices that comprise an electrolyte in contact with a colored active layer that becomes translucent or transparent when metal is placed in electrical contact with the active layer. While such chromatic devices work well, their electrolytes include an acid that, at least in some cases, makes fabrication of commercial chromatic devices more challenging. It would therefore be desirable to have chromatic devices that operate in a similar manner but that do not comprise an acid within the electrolyte.